JPS6226639Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a non-commutated switching device in which the driving rotation includes a switching element having a heat dissipation tab or a switching element requiring a heat dissipation plate, such as a power transistor, and these are assembled integrally with an armature. This invention relates to an electric blower with a structure in which a sub-motor is used as a drive source and blades are directly attached to the outer periphery of a rotor.

This type of electric blower includes a stator that integrates an armature coil, a position detector, and a drive circuit, a permanent magnet rotor, and a bearing that supports the shaft of this rotor.
The essential elements are the blades fixed to the outer periphery of the rotor, the base plate that supports the stator, and the case that covers the blades and forms ventilation passages.

As mentioned above, the drive circuit can be integrated with the armature, or it can be drawn out using lead wires and placed outside, but the former method is preferable because it has many advantages such as making the product more compact. Common.

A device in which the drive circuit and armature are integrated in this manner is generally arranged as shown in FIG.

FIG. 1 is a longitudinal sectional view of an electric blower using a TO-220 package power transistor as a switching element.

In FIG. 1, an armature 1, a position detector 2,
A printed circuit board 4 having a group of electronic components 3 constituting a drive circuit is attached to a base plate 5 to form a stator. A ring-shaped permanent magnet rotor 6 is attached to a rotating shaft 7 and rotatably supported on the outer periphery of the armature 1 via bearings 8. Blades 9 are attached integrally with the rotor 6 by an appropriate method such as press-fitting, bonding, or caulking on the outer periphery of the rotor. All of these are covered by a case 10 fixed to the base plate 5 to form a blower.

In the above configuration, the drive circuit is composed of the electronic component group 3 arranged on the printed circuit board 4 and the switching power transistor 11, and the switching power transistor 11 has the heat dissipation tab 12 facing the printed circuit board surface as shown in the figure. It is arranged between the printed circuit board 4 and the armature coil 13. An insulating film 15 is placed between the printed circuit board 4 and the base plate 5 in order to prevent the soldered parts 14 of the legs of electronic components from coming into contact with the base plate 5 and causing insulation defects.
and an appropriate spatial distance is maintained.

The output of a commutatorless motor is limited by the capacity of the switching element used, but in the above example, despite using the TO-220 package power transistor 11, which has a relatively large capacity, the tab 12 Since no heat sink is attached to the motor, the rated capacity of the transistor is limited, and the motor output cannot be increased to match the rated capacity of the transistor. Further, when the rotor outer diameter is smaller than the circumscribed circle of the tab tip, a considerably large gap _G1 must be provided between the base plate 5 and the blade 9 to avoid contact between the blade 9 and the tab tip. This means that if the thickness A of the blower is constant, it is restricted by the blade thickness _B1 , and therefore the air volume, which is the performance of the blower, is restricted.

The present invention is an attempt to improve the above-mentioned points, and a vertical cross-sectional view of one embodiment is shown in FIG. 2.
The embodiment in FIG. 2 is an example under the same dimensional constraints as in FIG. 1, and the same parts are given the same numbers. This will be explained below based on FIG. As shown in the figure,
The switching power transistor 11 is attached to the printed circuit board 4 so that the heat dissipation tab 12 faces the base plate 5.
It is fixed to the base plate 5 at a position in close contact with the base plate 5.

That is, the printed circuit board 4 is oriented in the opposite direction compared to the example shown in FIG. Since the position detector 2 needs to be placed in the same position as in FIG. 1, the soldering position will be changed.

With the above configuration, the same effect as when a heat sink is attached to the tab 12 of the power transistor 11 can be obtained, and the heat dissipation performance is dramatically increased. Therefore, the rated capacity of the power transistor 11 can be limited by using the heat sink. reduced to the value of the hour. The output of the blower can be increased by that amount. Furthermore, by bringing the heat dissipation tab 12 closer to the base plate 5, the gap _G2 between the base plate 5 and the blade 9 can be made smaller than the conventional gap _G1 , and the blade thickness can be reduced accordingly. B ₂ can be increased. Therefore, it is possible to achieve an increase in air volume commensurate with the above-mentioned increase in capacity under the same dimensional constraint A of the blower. On the other hand, if the air volume is the same, the size of the blower can be made more compact.

As described above, according to the present invention, in a blower using an external rotor non-commutator motor as a drive source, great effects can be obtained such as reduction in size and weight, improvement in air blowing capacity, and improvement in the reliability of the switching element. I can do things.

In the examples, a TO-220 package power transistor was used as the switching element, but the switching element is not limited to this and may be used with other package size switching elements that require heat dissipation and cooling, such as TO-92 or TO-126 small mold type, TOP-3 large mold type,
Or a mold type of a semiconductor manufacturer's own size located in between, and furthermore, such as TO-3.
It goes without saying that the present invention is useful even when using CAN type switching elements.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional electric blower, and FIG. 2 is a longitudinal sectional view of an electric blower according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Armature, 2... Position detector, 4... Printed circuit board, 5... Base plate, 6... Permanent magnet rotor, 9... Vane, 10... Case, 11... Switching element, 12 ... Heat dissipation tab, 13 ... Armature coil.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A stator comprising a rotor position detector and a printed circuit board provided with an armature coil and a drive circuit including a switching element for controlling energization of the armature coil; The drive source is an external rotor type non-commutated electric motor having a base plate supporting the stator, and a permanent magnet rotor located on the outer periphery of the stator and rotatably supported by a bearing. An electric blower is provided with a blower blade integrally attached thereto, which is covered with a case, and in which a heat dissipation tab of the switching element for energization control is arranged to face a base plate supporting a stator. (2) Utility model registration claim 1, in which an insulator is arranged between the heat dissipation tab of the switching element and the base plate, and the tab and the base plate are arranged in close contact with each other.
Electric blower as described in section.